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Bug#11761576 54082: HANDLE_SEGFAULT MAKES USE OF UNSAFE FUNCTIONS

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handle_segfault is the signal handler code of mysqld.  however, it makes
calls to potentially unsafe functions localtime_r, fprintf, fflush.



include/my_stacktrace.h:
  Add safe versions of itoa() write() and snprintf().
libmysqld/CMakeLists.txt:
  Move signal handler to separate file.
mysys/stacktrace.c:
  Remove unsafe function calls.
sql/CMakeLists.txt:
  Move signal handler to separate file.
sql/Makefile.am:
  Move signal handler to separate file.
sql/mysqld.cc:
  Move signal handler to separate file.
sql/signal_handler.cc:
  Remove unsafe function calls.
This commit is contained in:
Tor Didriksen
2011-11-30 15:39:29 +01:00
parent 98adda5095
commit 9a15f2492b
7 changed files with 620 additions and 242 deletions
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69
include/my_stacktrace.h
View File

@@ -1,5 +1,4 @@
/*
Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
/* Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@@ -12,8 +11,7 @@
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#ifndef _my_stacktrace_h_
#define _my_stacktrace_h_
@@ -63,6 +61,69 @@ void my_set_exception_pointers(EXCEPTION_POINTERS *ep);
void my_write_core(int sig);
#endif
/**
Async-signal-safe utility functions used by signal handler routines.
Declared here in order to unit-test them.
These are not general-purpose, but tailored to the signal handling routines.
*/
/**
Converts a longlong value to string.
@param base 10 for decimal, 16 for hex values (0..9a..f)
@param val The value to convert
@param buf Assumed to point to the *end* of the buffer.
@returns Pointer to the first character of the converted string.
Negative values:
for base-10 the return string will be prepended with '-'
for base-16 the return string will contain 16 characters
Implemented with simplicity, and async-signal-safety in mind.
*/
char *my_safe_itoa(int base, longlong val, char *buf);
/**
Converts a ulonglong value to string.
@param base 10 for decimal, 16 for hex values (0..9a..f)
@param val The value to convert
@param buf Assumed to point to the *end* of the buffer.
@returns Pointer to the first character of the converted string.
Implemented with simplicity, and async-signal-safety in mind.
*/
char *my_safe_utoa(int base, ulonglong val, char *buf);
/**
A (very) limited version of snprintf.
@param to Destination buffer.
@param n Size of destination buffer.
@param fmt printf() style format string.
@returns Number of bytes written, including terminating '\0'
Supports 'd' 'i' 'u' 'x' 'p' 's' conversion.
Supports 'l' and 'll' modifiers for integral types.
Does not support any width/precision.
Implemented with simplicity, and async-signal-safety in mind.
*/
size_t my_safe_snprintf(char* to, size_t n, const char* fmt, ...)
ATTRIBUTE_FORMAT(printf, 3, 4);
/**
A (very) limited version of snprintf, which writes the result to STDERR.
@sa my_safe_snprintf
Implemented with simplicity, and async-signal-safety in mind.
@note Has an internal buffer capacity of 512 bytes,
which should suffice for our signal handling routines.
*/
size_t my_safe_printf_stderr(const char* fmt, ...)
ATTRIBUTE_FORMAT(printf, 1, 2);
/**
Writes up to count bytes from buffer to STDERR.
Implemented with simplicity, and async-signal-safety in mind.
@param buf Buffer containing data to be written.
@param count Number of bytes to write.
@returns Number of bytes written.
*/
size_t my_write_stderr(const void *buf, size_t count);
C_MODE_END
#endif /* _my_stacktrace_h_ */